Slip expander asembly for well tools



.March 25, 1952 Filed Nw. 22, 194e ciwl ' im III 25 i I 1 /ZP I i 1 I l26 i i C. C. BROWN SLIP EXPANDER ASSEMBLY FOR WELL TOOLS 3 Sheets-Sheet1 lil INVENTOR.

Cprown @aha ATTORNEY March 25,' 1952 C. c. BRQWN 2,590,502

SLIP EXPANDER ASSEMBLY FOR WELL TOOLS Filed Nov, 22, 1948 A ssheets-sheet 2 INVENTOR. YC. C. Brown B v I ATTORNEY March 25, 1952 c.c. BROWN i SLIP EXPANDER ASSEMBLY FOR WELL TOOLS ATTORNEY Patented Var.25, 1952 OFFICE sLI'P EXPANDER ASSEMBLY FOR WELL rrooLs Cicero C. Brown,Houston, Tex.

Application November 22, 1948, Serial No. 61,450

(Cl. 16S-12) 2 Claims.

l This invention relates to improvements in well tools of the hook-Walltype, and particularly to an improved form of slip and slip expanderassembly for well packers.

Conventional types of hook-wall packers employ a plurality of toothedslip segments circularly arranged about a conical mandrel or expanderwhich is adapted, in cooperation with wedge shaped inner surfaces of theslips, to radially expand or retract the slips relative to a well pipein response to appropriate longitudinal movement of the expanderrelative to the slips. In such conventional packers, the primaryengaging surfaces of the expander and slips are made in the form ofsegments of regular cones. That is, the expander is a regular cone or afrustum thereof, while the inner surfaces of the slip segments arelikewise segments of a regular conical surface. However the exteriorfaces of the slips which are adapted to contact a pipe wall are normallyshaped in the form of cylindrical segments which have a generallyrectangular shape in elevational View, in order to provide maximum areafor contact with the pipe. It will be obvious, of course, that anytransverse cross section through the conical expander and the adjacentfaces of the ring of slips which is normal to the axis of the expander,`will be a circle, and that such circles will have different radii atdifferent elevations along the conical surfaces. As a result, as theexpander is moved axially relative to the inner faces of the slips, therelative circular radii will change, so that it becomes practicallyimpossible to maintain the inner faces of the slips in continuousbearing contact with the expander surface throughout the full area ofthe inner slip surfaces. As a result, although the inner faces of theslips may be in full contact with the expander surface at one position,at any other position the contacting surfaces become substantially aline contact extending longitudinally of the slips intermediate the sideedges thereof, the remainder of the slip area on each side of the centerline being caused to stand away from the expander surface. Since theslips have substantial length and breadth, the resulting separation isgreatest at the corners of the slips, so that when the outer faces ofthe slips are expanded into gripping contact with the pipe wall, asubstantial portion of the inner surfaces of the slips will beunsupported by the expander. When heavy expansive pressures are appliedthereto, as is the common condition, the slips will very often bebroken. To reduce this diniculty, conventional conical slip expandersand slips are designed for. setting in one particular ize of pipe so asto require a minimum of expansive movement to set the slips, and onesuch slip and expander assembly may not be used successfully in pipes ofdifferent sizes or having varying internal diameters.

Also, conventional slip and expander assemblies normally employ avariety of relatively complicated hinge linkages between the slips andthe slip cage in order to provide the requisite degree of flexibilityfor expansive and retractive movements of the slips contemporaneous withthe relative longitudinal movement between the cage and expander. Thismakes for a large number of loosely interconnected parts which, underthe great stresses to which such packers are subjected in ordinary use,renders them very liable to breakage or severe damage, particularly whenattempting to release the packer after it has once been set. Very oftenheavy jarring blows must be applied to the packer assembly to releaseit, and the loose linkages conventionally used will frequently beshattered by such blows, with the result that the packer will becomestuck in the well pipe, and may then be withdrawn or removed only withgreat difficulty and by costly procedures.

Accordingly, it is a primary object of this invention to provide a slipand expander assembly for well tools of the hook-wall type whicheliminates or obviates the principal disadvantages, such as aboveenumerated, to which more conventional constructions are commonlysubject.

In accordance with an illustrative embodiment of this invention, anexpander is employed which is in the form of a regular polygonal pyramidor frustum thereof, that is, a pyramidal body having a base in the formof a regular polygon, such as a triangle, square, pentagon, hexagon andthe like. There is thus provided a tapered body having avplurality ofcontiguous flat trapezoidal faces. A corresponding plurality of slipsegments are mounted for longitudinal sliding movement on these faces.The inner contact faces of the slip segments may, therefore, also bemade flat and tapered longitudinally to complement the slope of theexpander faces. The4 outer faces of the slips may be cylindrical andgenerally vertical, as well as rectangular in elevation, Acorrespondingin these respects to the more conventional types of slips. By employingthis novel geometric form of expander and complementary slips,.the fullareas of the inner faces of the slips will remain in continuous contactwith expander surface, irrespective of the degree of relativelongitudinal movement be'- tween them.

Additionally, the described construction permits an arrangement of theslips such that, when in fully'retracted position, they are insubstantial edge-to-edge abutment about the periphery of the expanderand present a substantially continuous cylindrical surface, with theresult that, when expanded, minimum separation of the slips will occurand the gripping load will be distributed over a maximum area of thepipe gripped thereby.

Further in accordance with an embodiment of this invention, there isprovided a novel form of collar member for connecting the slip segmentsto the slip cage. This collar member is constructed of interflttingarcuate segments which may be assembled with the slips and connected tothe cage in such a manner as to eliminate the need for the troublesomemulti-part wrist pin and linkage types of connections employed inconventional types of packers for connecting the slips to the slip cage.

Other and more specific objects and advantages of this invention willbecome apparent from the following detailed .description when read inconjunction with the accompanying drawings which illustrate anembodiment in accordance with this invention.

In the drawings:

Fig, l1 is an elevational view of a packer in accordance with anembodiment of this invention having some of 'the parts broken away andshown in position 'in a Ywell casing prior to being set therein;

Fig. 2 is a view similar to Fig. 1 showing the packer set in a wellcasing;

Fig. 3 is an'enlarge'd vquarter-'sectional elevation of a portion ofthepacker including lthe slips, slip expander and "cage portions, in theunset position corresponding to that shown in Fig. 1;

Fig. 4, is a view similar to Fig. 3 showing the same parts in the setposition;

Fig. 5 is a cross-sectional view looking upwardly along line KV5--5 ofFig. 3, through the slip and expander elements, having some of the slipsremoved therefrom for purposes of clearer illustration Fig. 6 is aVquarten-*sectional elevational view of theslip expander;

Fig. 7 is a perspective view showing the connections between the slips,fslipcollar and cage elements;

Fig. 8 is a cross-sectional view looking down along line 8-8 of Fig.'4;

Fig. 9 is a cross-sectional view along line 9-9 of Fig. 4;

Fig. 1-0 is a 4bottom exploded view of the slip collar; and Y Fig. lljis`a cross-sectional elevational view along `line -I -I-I I lof-Fig. V10.

Referring to `the drawings, and to Figs. 1 and 2, in particular, thereis shown, vby way of example, a packerof-the "hook-wall type, designatedgenerallyiby the lnumeral I-5, Vinserted vin a well casing I6, in whichthe `packer is to be set. As illustrated, the packer comprises'a tubularoperating pipe -I1jadapted to be connected at its upper end to a stringof tubing or -pipe I8 by which the packer is lowered'and raised in thewell and by means of which the operations of setting and releasing thepackerare eifected. Concentrically mounted'on'operating'pipe I1 is thepacker structure proper whichfcomprises a tubular sealing sleevelyconstructedvof rubber or other suitable and conventional flexible,resilient material which when subjected to end-wise compression isadapted "to be radially expanded into sealing engagement with casing I6.The upper end of sealing sleeve I9 carries a metal seat ring 2B whichisradapted to be engaged by an annular valve 2| 'carried on the upperend of the exterior of operating pipe I1, when tubing string I8 carryingoperating pipe I I is lowered. Seating of valve 2| on seat ring 20serves'to close the annular space between the "sealing sleeve andoperating pipe I1 and also acts to transfer the weight of the tubingstring to the upper end of the sealing sleeve when the latter issupported from below by the means to be described hereinafter.

Rigidly connected to the lower end of sealing sleeve I9 is the assemblyof parts which constitutes the principal subject matter of thisinvention. This assembly comprises a mandrel or expander, designatedgenerally by the numeral 22, a plurality of slips 23 which arecircumferentially arranged about the expander, a sleeve cage, designatedgenerally by the numeral 24, which is connected to the lower ends of theslips 23, by means of a slip collar, designated generally by the numeral25. The lower end of cage 24 carries a pair of lugs 26-26 which lareadapted to cooperate with la pair of slots 21 (only one shown) formed inelongated lug plates 28 larranged on opposite sides of the lower end ofoperating pipe I1. Lugs 26 and slots 21 form bayonet-type releasableconnections between the packer structure and the operating pipe. It willbe understood that when lugs 26 engage slots 21 the elements of thepacker structure will be held in the inoperative or retracted position,and the lugs are releasable from the slots in response to appropriaterotation of operating pipe I1 relative to the packer structure torelease the packer structure for setting inthe casing. The operations inthese respects are entirely conventional.

Expander 22 comprises a downwardly and inwardly tapering body 30, havingthe general form of a regular polygonal pyramid or frustum thereof. Inthe embodiment illustrated the body is in the form of a frustum of aregular hexagonal pyramid, its base being in the form of a regularhexagon (see Fig. 5). It will be understood that although this is aconvenient shape, the geometric form of the base may lbe that of atriangle, square, pentagon or other regular polygon. Accordingly, eachof Vthe sides 3| are in the form of regular trapezoids presenting aseries of nat downwardly and inwardly tapering surfaces about theexterior of the expander. Expander 30 is provided axially with acylindrical bore 32 concentric with operating pipe I1 which is freelymovable rotatively and longitudinally therethrough. The upper end ofbore 32 is internally threaded at 33 for threaded `engagement with ametalinsert 'ring 34 carried by the lower end of sealing sleeve I1 (seeFigs. 3 and 4). Set screws 35 extend through the wall of the expanderadjacent its base to lock the expander to insert ring 34. A plurality ofp'assageways 35 extend radially through the wall of expander 3H at thejunctions of sides 3| and are spaced slightly below threaded connection33 to provide communication between bore 32 and the exterior of theexpander.

Slips 23 comprise generally rectangular sectors cf a cylinder, theexternal diameter of which is normally slightly less than the internaldiameter of casing I6. The slips will preferably be formed by cutting acylindrical blank `along an appropriate number of radii to form therequisite number of slips, whereby the slips, whenvin retractedposition, will have their side edges in relatively close contact to forma substantiallycontinuous cylindrical exterior surface. The Vexternalfaces of the slips are provided with series of rows of downwardly facedgripping teeth 31. In longitudinalsection slips 23 are wedge-shapedhaving inner faces 38 which are at and taper upwardly and outwardly atan angle complementary to that of the adjacent faces 3| of the expander.Each of the faces 3| carries a dove-tail'spline 39 extendinglongitudinally of its medial portion which is engageable with a,complementary groove 40 out in faces 38 of the slips. The splinedconnection thus formed permits relative longitudinal movement betweenthe slips and the expander while holding the slips locked to theexpander. It will be understood that the splines may be on the slips andthe grooves on the expander faces without altering the essentialoperating characteristics of the structure. The lower end or base ci'each of the slips 23 is provided with an integral tongue 4| having aT-shaped head which is adapted to be received in a complementary T-slot42 formed or out in the upper edge of slip collar 25. lThe relativedimensions of heads 4| and 42 are made such that heads 4| fit somewhatloosely in slots 42 and may engage in some movement relative thereto,particularly in the radial direction. Collar 25 comprises a plurality ofinter-tting circular segments 43 (see Fig. 1) particularly) adapted tobe connected together by means of dowel pins 44, one of which is screwedinto one end of each of the segments and is adapted to be slidablyreceived in a suitable socket 45 in the adjacent end of the contiguoussegment. In assembling the slips on the expander, the grooves 49 in theslips are engaged with splines 39 on the expander. Segments 43 of theslip collar are then connected to tongues 4| by slipping the segmentslaterally about the tongues with T-slots 42 engaging the T-heads in themanner illustrated. As the segments are thus moved radially inwardly,the dowel pins are brought into engage- -ment with their cooperatingsockets and the collar thus locked about the tongues and slips to lockthem about the expander. The lower end of collar 25 is provided with anexternally threaded extension 45 of somewhat smaller external diameterthan the body of the collar.

Gage 24 comprises a tubular body 41 concen trically arranged onoperating pipe |1 and internally threaded at its upper end so that itmay be screwed on extension d5 of the slip collar after the latter isassembled and connected to the slips as above described. With thisarrangement the upper end of cage body 41 forms a rigid circular keeperor lock for the collar segments which will prevent their separation inuse and additionally assure positive locking of the r slips about theexpander. Cage body 41 is provided with a plurality of T-shaped radialsockets 48 (see Fig. 8) in which are mounted correspondingly shapedblocks 49 having projections or ribs 50 on their outer faces. springs 5|are arranged between the inner faces of blocks 49 and the bottom ofsockets 48 and are adapted to normally urge blocks 49 outwardly to forceribs 50 into frictional engagement with the inner wall of casing lli.Blocks 49 have longitudinal edge anges 52 which cooperate with the inneredges of sockets 48 to retain the blocks within the sockets. The lowerend of cage body 41 is externally threaded at 53 for connection theretoof a sleeve 54 which carries lugs 26 on its inner surface. A pluralityof ports 55 provide communication between the bore of sleeve 54 and theexterior thereof. It will be understood that the described form of cage24 and friction blocks 49 is intended to be merely illustrative of thevarious types of cages conventionally used in well packer structures forproviding frictional engagement with a casing wall. Other suitable andconventional forms of friction cages may be employedfor this particularportion ofthe A plurality of coil I described structure, the detailedconstruction of such cages forming no essential part of this invention.

Operation of the above-described structure is as follows: The packerstructure is assembled on operating pipe I1 with lugs 26 engaged inslots 21 to hold the slips 23 and sealing sleeve |9 in their retractedpositions as illustrated particularly in Figs. 1 and 3. The upper end ofoperating pipe |1 will be connected to pipe string I8 and the packerstructure lowered thereby into casing I5. It will be understood thatother well tools may be connected to the lower end of oper ating pipe |1if desired and in accordance with conventional practice. Also, mud fluidor other fluids may be circulated through the pipe string and up outsidethe packer during the lowering operation. Passageways 55 will allowfluidto enter the annular space between the packer and operating pipe |1and discharge back into the annular space outside the packer throughpassageways 36 and through seat ring 29. This is a more or lessconventional arrangement to permit the packer to move through the casingwith minimum resistance from any fluid in the casing and to maintaincirculation while the packer is in movement. When the packer has beenlowered to the desired position in the well, pipe string 8 and operatingpipe |1 will be rotated in the appropriate direction a sufdcient amountto release lugs 26 from slots 21. The frictional engagement maintainedbetween blocks 49 and the casing wall under the pressure of coil springs5| will hold the packer structure stationary while permitting relativerotation of operating pipe I1 to eiect release of lugs 26 fro-m slots21. Fig. 1 illustrates generally the position of the parts of thestructure just following the withdrawal of the lugs from the slots. Uponrelease-of the pins from the slots pipe string I9 and operating pipe |1are lowered relative to the packer structure until valve 2| contactsseat ring 20. As the weight of the pipe string is thus transferred tothe upper end of sleeve I9, the latter will drive expander 39 downwardlyrelative to slips 23 which will be held stationary through theirconnection to cage 24 which is, in turn, held in stationary position bythe fri-ctional engagement of blocks 49 with the casing. The movement ofthe expander relative to the slips will cause the latter to slideupwardly over the descending faces 3| of the expander, the wedgingaction of the complementary surfaces forcing the slips radiallyoutwardly until teeth 31 engage the wall of casing I6. This effectivelystops further downward movement of the expander and sealing sleeve andcontinued application of the weight of pipe string I8 will increase theexpansive pressure on the slips to cause the slips to grip the casingmore tightly. Also the resistance to further downward movement,resulting from engagement of the slips with the casing, will cause theweight applied to the upper end of sealing sleeve |9 to expand thelatter radially and thereby effectively seal the annular space betweencasing I9 and operating pipe l1, thus providing the pack-oft which isthe primary purpose of the structure. Figs. 2 and 4 illustrate thepositions of the parts when the packer has thus been set. Contact of ofvalve 2| with seat ring 29 will cut off uid communication between thesections of casing |6 above and below sealing sleeve I9, thus eiectivelyisolating the sections lfrom 'each other. Passageways 36 and 55 willalso serve as relief ports t0 prevent entrapment of fluid between theparts of the packer during ,relative movement thereof which mightotherwise hinder its proper functioning.

It will be evident that by virtue of the novel construction of theexpander and slips herein described, -the slips will be fully ksupportedover the entire area of their inner lfaces by the expander surfacesirrespective of the degree of relative longitudinal movement betweenthem. Thus, one suitably dimensioned set of slips and expander may beemployed in casings of considerably varying size while maintaining thisfull surface contact, and maximum expansive pressures may thus beapplied to the slips without danger of breakage. Also by the selectionof an expander having a suitable number o f polygonal faces and ofsuitable slope, a number `of slips may be employed such that minimumseparation will occur between the contracted and fully expandedpositions and thereby provide a maximum area of toothed surface forgripping the casing. Since the outer periphery of the ring of slips iscircular, this permits a uniform distribution of the slip pressure aboutthe entire circumference of the casing and obviates a difficulty commonto the more conventional types o f hookwall packers in which the slipsegments become rather widely spaced when expanded to their setpositions and, therefore, are caused to concentrate their pressures atrather widely spaced vpoints on the casing wall. This frequently has theresult that, under the very high pressures to which the packers aresubjected, such separated slips -bulge the relatively limited casingareas against which the kslip faces are pressed. Such bulging may notonly damage the casing but may cause the slips to become locked intothe-bulged portions so that they become diiicult to release.

To eiect release of the packer, pipe string I8 is raised to release thepressure on sealing sleeve, allowing it to retract -while the operatingpipe is drawn upwardly. The upward movement of operating pipe `I-l willbring the upper ends of plates `28 into contact with the apex ofexpander 3l). The upper ends of plates .28 form shoulders or abutmentswhich coact with the lower Aend of the expander to force the latter inthe upward direction relative'to slips 23. This movement will actthrough the splined connections of the expander with the slips topositively retract the latter out of engagement with the casing wall andthereby7 e'ect release of the packer. The entire packer may then bewithdrawn from the well. Plates 28 may be used as jar lugs to strikeupward blows `against the'lower end of the expander in the event-suchblows are necessary to effect release of the slips and sealing sleevefrom the casing wall. `Various other and more conventional forms of suchjarring mechanisms may be employed for this purpose. By the describedconstruction of slip collar 25 and its connections to the 'slips vandcage, it will be seen the conventional looselinkages commonly employedfor hngedly connecting the slips to the cage have been eliminated, andreplaced by a single connection formed -by T-heads 4I and slots 42, theT-heads being generally radially movable in the slotsduring relativemovement between the slips and expander. The relatively massive andunitary construction thus provided permits the packer structure to besubjected to extensive vjarring action, whenvnecessary,.with no dangerof breakage-orserious damage.

It willbe understood that .various valterations and changes may be madelin the details of the illustrative embodiment without departing fromthe r scope of the appended claims but within the spirit of thisinvention. In particular, it will be understood that the described slipand expander assembly may be employed for upward setting, as well as inthe downward setting arrangement herein described by minor reversal andsuitable rearrangement of the parts in a manner which will be clearlyevident to those skilled in this art. While the slips and expanderassembly has been illustrated as used with a well packer, this is merelyby way of illustration and it will be understood that the invention maybe employed with other forms of hook-wall well tools, such as spears,various fishing tools, and the like.

What I claim and desire to secure by Letters Patent is:

1. In well tools of the hook-wall type, an improved slip andslip-expander assembly, comprising, an expander shaped in the form of aregular polygonal pyramid, slip members disposed for longitudinalsliding movement on the several faces of said expander, the innersurfaces of said slip members being generally at and of complementaryslope to said faces, interlocking longitudinally splined connectionsbetween said slip members and said faces, a segmental collar memberhaving at one end thereof radially movable inter-locking tongue-and-slotconnections with the base of each of said slip members and an externallythreaded extension at its other end, an internally threaded tubularkeeper member threadedly engageable about said extension, said collarmember being composed of a plurality of separable arcuate segmentshaving radially abutting end faces, a socket having a closed end in oneof said end faces of each of said segments, and a dowel embedded in theother end face of each of said segments and slidable into the opposedsocket in the adjacent end face for circularly joining said segments.

2. In well tools of the hook-wall type, an improved slip-expanderassembly, comprising, a tapered slip expander, a plurality of slipsannularly disposed about the exterior of said expander for longitudinalsliding movement thereon, and a slip-retainer collar member havingradial tongue-and-slot connections at one end thereof with said slipsand an externally threaded extension of smaller diameter than the bodyof said collar member at its other end, and an internally threadedtubular keeper member enclosing said extension, said collar member beingcomposed of a plurality of separable arcuate segments having radialabutting end faces, a socket having a closed end in one of said endfaces of each of said segments, and a dowel embedded in the other endface of each of said segments and-slidable into the opposed socket inthe adjacent end face-for circularly joining said segments CICERO c.BROWN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,428,385 Meredith et al Sept. 5,1922 2,275,935 ABaker g, Mar. 10, 1942 2,331,185 Gordy Oct. 5, 194312,343,075 .Otis Feb. 29, 1944 :2,368,401 Baker Jan. 30, 1945

